When tightening or loosening bolts or nuts, it is necessary to have the correctly sized spanner and the like. Using a spanner that is even slightly larger than the nut or bolt can result in damage to the fastener which is highly undesirable.
Adjustable spanners are, of course, well known, but because of their large head size, there will be many situations where an adjustable spanner cannot be used due to space constraints and the like.
Nuts and bolts do not have any indication of their size given anywhere on the fastener and therefore there is always a degree of guesswork before the correct spanner can be used.
It is also reasonably common to have nuts and bolts in relatively inaccessible places and it is extremely inconvenient to have to use a relatively large number of spanners in order to find the spanner which will fit the fastener head.
However, not every possible solution to this problem will find acceptance in the marketplace.
For instance, it may be possible to have a finger member (for instance a thin blade) formed with a number of centralised openings which correspond with different fastener head sizes such that the finger member can be placed over the nut to find the correct fastener size before a spanner is required. However, is not convenient to have a large number of notches on a single finger member as their may be space constraints that will not allow the finger member to be pushed further along such that the fastener can be lined up with a correct notch on the finger member. Therefore, it would be advantageous to have a plurality of finger members each with one or relatively few “notches” as this will allow the finger member to be used in confined spaces. However, if these finger members are not properly designed, it can be almost just as inconvenient to have to select from a large number of finger members as it would be to simply use a large number of spanners. Having centralised openings requires the finger member to be placed over the nut or bolt which obscures it which is not desirable.
It is also not a totally satisfactory solution to simply pin the finger members together. This is because one finger member will need to be inserted around the fastener such that the size of the fastener can be determined, but the other finger members will be in the way, can snag against adjacent equipment, and be generally inconvenient.
Therefore, there would be an advantage if it were possible to provide some form of nut and bolt sizing or gauging device or tool which could be used to size a relatively large range of bolts and nuts or similar items that need to be sized, and where this can be done in a convenient manner and therefore where the device/tool will find acceptability to the consumer.